let grep rex ml_name =
  let lb = Linebuffer.create () in
  let annot_name = Filename.chop_extension ml_name ^ ".annot" in
  let line_num = ref 0 in
  let rec process () =
    Linebuffer.get_line 
      lb
      (fun line ->
	 incr line_num;
	 if
	   try
	     ignore (Pcre.pcre_exec ~rex line);
	     true
	   with Not_found -> false
	 then
	   Printf.printf "%s:%d:%s\n" ml_name !line_num line;
	 process ();
      )
  in
    process ();
    try
      Annotator.merge ml_name annot_name (Linebuffer.feed lb)
    with Sys_error message -> Printf.eprintf "%s:%s\n" ml_name message

let main () =
  let sources = ref [] in
  let re = ref None in
    Arg.parse [
    ]
      (fun s -> 
	 match !re with
	   | None -> re := Some (Pcre.regexp ~study:true s)
	   | Some _ ->
	       sources := s::!sources
      )
      "Grep Objective Caml source files compiled with annotations (-dannot or -dtypes) from their annotated forms";
    sources := List.rev !sources;
    match !re with 
      | None -> failwith "no regular expression"
      | Some re ->
	  match !sources with
	    | [] -> failwith "no source files"
	    | sources -> List.iter (grep re) sources

let () = main ()